Ladder tape



G. F. BRENT LADDER TAPE Dec. 4, 1951 Filed April 50, 1949 2 Q m Q 1 K lh 2 0 A 6 2 A b v 7 M 4% 2 Fi 6. Fly. 2

v Zhwemor Georye F571 Cittornegs Patented Dec. 4, 1951 LADDER TAPEGeorge F. Brent, Pittsburgh, Pa., assignor to Hunter-DouglasCorporation, Riverside, Calif... a corporation of Delaware ApplicationApril 30, 1949, Serial No. 90,625

Claims.

. My invention relates to Venetian blinds, and particularly to theflexible hangers or ladder tapes for supporting the slats of the blindsin suspended position within the area of the Window or other opening tobe screened.

The usual Venetian blind hanger or ladder tape comprises a pair ofelongate, relatively narrow, flexible straps which are spaced apart inparallelism and transversely interconnected by a series of flexiblecross bands. The cross bands are spaced apart at uniform intervalslongitudinally of the pair of straps.

In service two or more ladder tapes are secured in horizontally spacedrelation to a horizontal supporting bar pivoted at the top of the windowor other opening to be screened. The ladder tapes extend in parallelrelation vertically downward from the horizontal bar, with the crossbands of the ladder tapes aligned horizonta ly, to provide support forthe slats of the blind structure.

The usual ladder tape is constructed of woven fabric, and the union ofthe cross bands to the vertical straps is effected by interweaving theends of the cross bands with the bodies of the straps. The ladder tapesas thus constructed are of neat and pleasing appearance, and, when new,they afford the intended utility. However, such ladder tapes arerelatively expensive, and,

being formed of fabric, they tend to shrink and to become distorted whenthey are washed, as they must be from time to time in service.Furthermore, the fabric ladder tapes are, forartistic reasons, coloredor dyed in desired hues, but under the effect of sun rays and light thecolors tend to fade, thus detracting from the desired appearance of theVenetian blind structure.

The object of my present invention is to provide an improved ladder tapestructure for Venetian blinds which may be constructed of an inexpensivematerial and in an inexpensive manufacturing procedure. It is further myobject to provide a ladder tape which will endure cleaning withoutshrinking, fading, or becoming distorted. Other objects will be apparentin the ensuing specification.

In accordance with my invention, I form a novel ladder tape structure ofa plastic material which is highly flexible, capable of being colored inlustrous and enduring hues, resistant to objectionable distortion underthe weight of the supported slats, and adapted for manufacture in awelding or fusing operation, as will presently appear.

The invention will be understood upon reference to the accompanyingdrawings, in which:

Fig. 1 is a fragmentary view in front elevation of a Venetian blind inwhich a ladder tape of my invention is embodied;

Fig. 2 is a fragmentary View, presenting the ladder tape as it appearsfrom the right of Fig. 1, the view in Fig. 2 being presented on largerscale than Fig. 1, with the ladder tape shown partly in elevation andpartly in medial, vertical section;

Fig. 3 is a view in horizontal section of the ladder tape, as shown onthe plane III-III of Fig. 2;

Fig. 4 is a view comparable with Fig. 3, illustrating a modification instructural detail;

Fig. 5 is a view generally similar to Fig. 2, illustrating furthermodifications in the construction of the ladder tape of this invention;and

Figs. 6 and '7 are views similar to Figs. 2 and 5, severallyillustrating still other modifications in details of construction.

Referring to the drawings, Fig. 1, illustrates only so much of asimplified form of a Venetian blind structure as is necessary for adescription of the invention. The illustrated blind comprises asupporting bar 2 which carries pins 3 at its two ends, by means of whichthe bar jslats 8 in vertically spaced relation, the slats beingindicated in full lines in Fig. 1, and in broken lines in Fig. 2. Itwill be understood that the ladder tapes 4 are secured at their lowerends to a basal bar (not shown), and that the blind structure mayinclude means for tilting the supporting bar 2 on the horizontal axis ofits aligned pivots 3, whereby the front and back straps 5 and 6 may bevertically shifted relatively to each otherthe front straps 5 upwardly,and the back straps 6 downwardly, or vice-versa, with the efiect thatthe cross bands 7 and the slats borne thereby are tilted in well-knownmanner.

The conventional Venetian blind includes at least two vertical adjustingcords 9. These cords are anchored at their lower ends to the lowermostslat or basal bar of the blind structure, and extend upwardly throughopenings, provided therefor in the slats e and cross bands I, to thesupporting bar 2, whence the cords are trained over pulleys (not shown)and extended to one side of the blind structure, to provide pull-cordsfor drawing the slats vertically together and regulating the effectivevertical extent of the blind structure. As the slats are thus drawnvertically together the intervening portions of the straps 5 and 6 ofthe ladder tape buckle or gather in known way. For further detail of aVenetian blind structure of the sort here alluded to, and in order toexemplify the various types of blinds in which the ladder tape of myinvention may be used, reference is made to Letters Patent No.2,012,034, granted to me on August 20, 1935.

The cross bands I of the ladder tape comprise loops formed in and offsetlaterally from the bodies of the straps. The simplest form of thestructure is shown in Fig. 5, in which the cross bands I consist ofloops formed in the strap 5. The two limbs of each loop are united on aline H! at the plane of thestrap 6, and the closed end or bight of theloop is united, as at H, to the inner face of the strap 5. The limbs ofthe loops, thus forming the cross bands l of the ladder tape for thesupport of the slats 8, may be cemented or fused (as will presentlyappear) in face-to-face contact, as shown in Fig. 5, or

the loops may be united only on the lines Ilia and Ila, as shown in Fig.6, and the slats 8a slid into position and supported between the limbsof the loop. Elliptical orifices l2 are formed in cross bands forregistry with the usual openings formed in the slats for the passage ofthe adjusting cords 9, Figs. 1 and 2.

In Fig. '7 it will be seen that the cross bands 1 "lb may be formed by aseries of spaced loops formed in both of the vertical straps 5b and 6bof the ladder tape structure. Each loop is closed and united on a linelfib at the plane of the strap in which the loop is formed, so that thecontinuity of the strap is in effect uninterrupted, as in the case' ofthe other structures described. However, in the structure of Fig. '7,the loops need not extend across the entire interval between the twovertical straps, but only half way,

where the loops are united pair by pair, on lines indicated at Hb, toform the cross arms lb of the ladder tape.

Returning to Figs. 1 to 3, the cross arms 1 will be seen to be alsoformed by loops offset from the bodies of both straps 5 and 6, but inthis case the loops are such in length that they may be overlapped andunited, as shown in Fig. 2,

thereby affording, in those cases where desired, greater strength andsecurity of the loops than is had in the structure of Fig. 7. Fig. 3illustratesin plan the orifices [2 formed in the cross arms I for thepassage of an adjusting cord 9,

and Fig. 4 illustrates a valuable feature of structural detail; that is,a slot l3 may be formed in each cross band of the ladder tape, the slotextending outwardly from each orifice l2 and opening through one of thelateral edges of the cross band, whereby the ladder tape may bedisengaged from the cords 9 without removing the cords from engagementwith top and bottom bars of the blind structure. This facilitates theremoval 'of the tapes for cleaning or renewal.

It has hitherto been proposed that ladder tapes be constructed of stripsor hands of a highly flexible thermoplastic material, such as apolyvinyl chloride, ethyl cellulose, cellulose acetate, celluloseacetate butyrate, methyl methacrylate, polyethylene, or other suitablethermoplastic substance. Indeed, strips or bands of cloth impregnatedand/or coated with such plastic material have been proposed. Inaccordance with my invention I not only may form my improved ladder tapeof such a material, but I have discovered that the described union ofthe loops may be efiected by welding; that is, by the application ofpressure and heat in the areas or on the lines where union is desired,the plastic substance of the tape is so far softened that a fusion andweld is effected. More specifically, by applying heat and pressure alongthe lines 10 where the loops are secured at the plane of the straps 6(and/or 5) the desired permanent union is obtained. Also, the union (Hand Ila) of the closed ends or bights of the loops with the strap 5 maybe effected, and so too the union of the paired loops in the structureof Fig. 7 is effected on the lines llb. Additionally, the two limbs ofeach loop may be permanently welded face to face over their entirecommon area, or they may be united on one or more lines of weld, thedotted lines M in Fig. 3 illustrating a single line of weld. In thestructure of Figs. 1 to 3, the overlapped loops may be welded over theirentire common area, or over such lines of weld as may be desired.

The foregoing specification will provide to those skilled in the art afull understanding of my invention, and the modifications and variationspermissible without departing from the spirit of the invention definedin the appended claims will be apparent.

I claim:

'1. In a ladder tape for Venetian blinds comprising two fiexible strapsextending in parallel spaced relation and provided with cross bands atlongitudinally spacedv intervals for the support of slats; the inventionherein described wherein said cross bands comprise loops formed in andoffset from the body of one of said straps, with the two limbs of eachloop welded face to face and securely united at the plane of the strapin which it is formed, to maintain strap continuity, and extendedlaterally therefrom and united to the other strap.

2. In a ladder tape for Venetian blinds comprising two flexible strapsextending in parallel spaced relation and provided with cross bands atlongitudinally spaced intervals for the support of slats; the inventionherein described wherein said cross bands comprise loops formed in andoffset laterally from the bodies of said straps, with the two limbs ofeach loop united at the plane of the strap in which it is formed, tomaintain strap continuity, the loops formed in the two straps beingunited pair by pair to form said cross bands.

7 3. In a ladder tape for Venetian blinds com,- prising two flexiblestraps extending in parallel spaced relation and provided with crossbands at longitudinally spaced intervals for the support of slats; theinvention herein described wherein said, cross bands comprise loopsformed in and offset laterally from the bodies of said straps, with thetwo limbs of each loop united at the plane of the strap in which it isformed, to maintain strap continuity, the loops formed in the two strapsbeing overlapped and united pair by pair to form said cross bands.

4. In a ladder tape for Venetian blinds comprising two flexible strapsextending in parallel spaced relation and provided with cross bands atlongitudinally spaced intervals for the support of slats; the inventionherein described wherein said cross bands comprise loops formed in andofiset laterally from the bodies of said straps, with the two limbs ofeach loop united at the plane of the strap in which it is formed, tomaintain strap continuity, the loops formed in the two straps beingunited pair by pair to form said cross bands, and medial openings formedin the paired and united loops to provide cord passages.

5. In a ladder tape for Venetian blinds comprising two flexible strapsextending in parallel spaced relation and provided with cross bands atlongitudinally spaced intervals for the support of slats; the inventionherein described wherein said cross bands comprise loops formed in andoffset laterally from the bodies of said straps, with the two limbs ofeach loop united at the plane of the strap in which it is formed, tomaintain strap continuity, the loops formed in the two straps beingoverlapped and united pair by pair to form said cross bands, and medialopenings formed in the overlapped and united loops to provide cordpassages.

6. The structure of claim 1, with medial openings formed in the bodiesof such loops to provide cord passages, and slots extending from saidopenings through one edge of each cross band formed by said loops.

7. The structure of claim 5, with slots extending from said openingsthrough one edge of each cross band formed by said loops. 7

8. A ladder tape for Venetian blinds including two flexible strapscomprised of thermoplastic material and extending in parallel spacedrelation, and a series of loops formed at regular longitudinally spacedintervals in the body of one of said straps only, with the two limbs ofeach loop closed face to face and united in a weld at the plane of thestrap in which it is formed, said loops extending from the latter strapand being welded at the bights in the loops to the other strap to formslat-supporting cross bands.

9. A ladder tape for Venetian blinds including two flexible strapscomprised of thermoplastic material and extending in parallel spacedrelation, and a series of loops formed at regular longitudinally spacedintervals in the bodies of said straps, with the two limbs of each loopclosed and united in a weld at the plane of the strap in which it isformed, said loops extending from said straps and being united in weldspair by pair to form slat-supporting cross bands.

10. A ladder tape for Venetian blinds including two flexible strapscomprised of thermoplastic material and extending in parallel spacedrelation, and a series of loops formed at regular longitudinally spacedintervals in the bodies of said straps, with the two limbs of each loopclosed and united in a weld at the plane of the strap in which it isformed, said loops extending from said straps and being overlapped andunited in welds pair by pair to form slat-supporting cross bands.

GEORGE F. BRENT.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,937,342 Higbie Nov. 28, 19332,229,225 Schneider Jan. 21, 1941 2,405,579 Hunter Aug. 13, 19462,537,865 Stuber et al Jan. 9, 1951

